Frequently Asked Questions
Everything you need to know about CLIF, how it compares to other data models, and how to join our growing consortium
01 Governance & Structure
CLIF is a strictly federated consortium of collaborative research labs. Participation is entirely optional and flexible—each site may choose how and when to engage.
Key principles:
- All participating sites maintain independent IRB approval and retain full responsibility for their own IRB processes
- CLIF does not involve the sharing of patient-level data—all analyses are performed locally
- Because no patient-level data is exchanged, no data user agreements (DUAs) are required between sites
This federated approach ensures maximum flexibility while maintaining rigorous ethical standards and data privacy protections.
02 Technical Details
CLIF captures detailed ICU data including ventilator settings throughout the stay (FiO2, PEEP changes), vasoactive drug titrations, and other critical parameters. While the schema supports high-frequency data, current federated analyses focus on clinically meaningful time intervals that balance detail with practical research needs.
A lead principal investigator (PI) originates a project idea, specifies the required cohort and CLIF tables for the project, and then develops analytic code written using their local CLIF database. The CLIF consortium then runs the script and returns aggregate results to the PI. The PI compiles the aggregate results for publication.
At no point is patient-level (i.e. “row-level”) data exchanged between sites, unless there is a specific Data Use Agreement (DAU) that permits this for specific combinations of consortium sites and directionality. You can submit your project idea here!
The current CLIF framework is for standardized longitudinal ICU data elements (e.g. labs, vitals, ventilator settings, medication doses, and flowsheet documentation). We believe the clinical context defined by these standardized minimum Common ICU Data Elements (CDE) are essential for the proper interpretation of multi-modal data such as clinical notes and imaging results.
Once CLIF is mature for these standardized data elements, we plan to represent these multi-modal data.
Established open-source CDMs such as the OMOP take on data harmonization and standardization challenge for the entire EHR. The work of the Observational Health Data Sciences and Informatics (OHDSI) community has been a guiding force for the CLIF consortium throughout CLIF's development. However, the extract-transform-load (ETL) to a CDM is a major data engineering challenge, and data elements essential for the study of critical illness typically are not prioritized. Local CDM instances often completely omit granular critical illness data elements, such as ventilator settings for patients suffering from respiratory failure.
For practical guidance on implementing CLIF ETL pipelines and overcoming these challenges, visit our Implementation Guide, which includes EHR-specific resources and best practices.
CLIF is designed for critically ill hospitalized adults and does not represent outpatient encounters. The patient, hospitalization, and admission_diagnosis table summarize information about the patient on admission to the hospital. CLIF could be used as one part of a larger EHR study that requires outpatient data from before the admission.
CLIF is currently not linked to established interoperability standards like Health Level Seven (HL7) Fast Healthcare Interoperability Resources (FHIR). Future data engineering directions include the development of HL7 FHIR queries to generate real-time CLIF tables.
The CLIF consortium is committed to the responsible conduct of research. Each consortium site has independent IRB approval or an exemption for each CLIF project they run on their local CLIF database.
The consortium is aware of the NIH Single Institutional Review Board (IRB) policy and planning to adhere to this policy for future NIH-funded projects using the consortium.
03 Getting Started
The CLIF consortium is committed to an inclusive, open-source development ecosystem. We recognize that not all investigators have the resources or institutional support necessary to extract-transform-load (ETL) their local healthsystem’s data into CLIF. Therefore, we will run any high-quality observational study coded to run on CLIF.
We have developed a pipeline to convert the de-identified exemplar MIMIC-IV dataset into a high-quality CLIF database. For setup instructions and guidance on creating it at your site, please refer to this GitHub repository.
We welcome new collaborators! The CLIF consortium is actively growing, with 17 institutions already participating and 12 sites contributing data. To join:
- 1. Contact us at
- 2. We'll schedule a call to discuss your institution's needs and capabilities
- 3. Our team will guide you through the implementation process
- 4. Join our collaborative research network
We're excited to support innovative critical care research projects! Please email us at with a brief description of your project. Our scientific committee reviews proposals and can help connect you with participating sites and resources.
To ensure successful and reproducible research across the consortium, we recommend following these best practices:
- 1. Use the official project template — Start your project using our CLIF Project Template which provides standardized code structure and documentation
- 2. Buddy coding with another site — Pair with a researcher from a different institution to validate your code works across different CLIF implementations
- 3. No patient-level data exports — Never export or share patient-level (row-level) data between sites
- 4. Minimum cell counts — All aggregate results must contain data from more than 10 patients per cell to protect patient privacy
Have More Questions?
We're here to help! Whether you're interested in implementing CLIF, proposing research, or learning more about our consortium, don't hesitate to reach out.
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